In camera copy work it is often desired to mount a film sheet on a camera back, to subsequently remove that film sheet and to thereafter re-mount the film sheet in precisely the same location on the camera back. Accordingly, various forms of registry pins and other registry structures heretofore have been provided for this purpose. However, these previously known forms of registry pins and other registry devices require either preapertured film sheets, special mounting frames which are not adaptable for use in conjunction with a copy camera back or other structures which are not compatible with screening photography copy work and do not provide protection for a contact screen to be disposed thereover. Accordingly, a need exists for an apparatus which will be capable of allowing successive mounting of a film sheet on a copy camera back in precisely the same location.
Examples of various different forms of registry devices including some of the general structural and operational features of the instant invention are disclosed in U.S. Pat. Nos. 2,760,273, 2,983,049, 3,253,339, 3,625,611, 3,751,817, 3,771,870 and 3,957,371.